Gasless Combustion Synthesis from Elements

Powder Chemical Composition (wt %) Main Impurities (wt %) Average Particle Size (/rra) or Specific Surface Area (m /g) 

Cemented Carbide Alloy Basic Composition Density (g/cm ) Average Grain Size (urn) Hardness (HRA) Ultimate Flex Strength (kg/mm ) Application 

STIM-3B T1C-CT3C2+steel 5.40 2-4 92.5 100-120 Corrosion- resistant articles 

Kharatyan and Nersisyan (1994) reported an alternative method of activating the reaction between Si and C without preheating. Potassium nitrate (KNO3) is used as an activating agent. With this method, fine ( l-/tm) SiC powders containing 28-29 wt % bound and 0.5 wt % free carbon were produced. 

It has been demonstrated that most of the transition metal borides can be synthesized in the SHS mode (Holt et al, 1985 Rice et al, 1987 Mei et al, 1992 Fu et al, 1993a Li, 1995). Early works reported synthesis of relatively pure (with residual unreacted boron less than 0.3 wt %) ZrB2, TiB2, HfB2, and MoB (Merzhanov and Borovinskaya, 1972 Hardt and Holsinger, 1973). Combustion- 

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From the viewpoint of chemical nature, three main types of CS processes can be distinguished. The first, gasless combustion synthesis from elements, is described by the equation... 

Based on their analyses, and incorporation of additional details, we have outlined some general relationships for gasless combustion synthesis of materials from elements (type 1), as shown schematically in Fig. 3. Both characteristic features of the process, the combustion wave propagation velocity and maximum temperature, have maximum values when the composition of the green mixture corresponds to the most exothermic reaction for a given system (Fig. 3a). In gen-... 

From the viewpoint of chemical nature, three main types of CS processes can be distinguished. The first is a gasless CS from elements. The second type, the so-called as-so//d combustion synthesis, involves at least one gaseous reagent in the main combustion reaction. And the third type of CS is reduction CS. In this chapter, we consider the gas-solid type of CS, which in general can be described by the following overall reaction formula ... 

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